- This topic has 6 replies, 3 voices, and was last updated 7 years, 7 months ago by
Damian Marek.
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September 30, 2016 at 8:32 am #41388
Tayyab Mehmood
ParticipantHi, I am trying to do QPSK/16QAM Hierarchical modulation with High-priority (HP) QPSK signals and the Low-priority (LP) 16 QAM signals. But unable to add them to see them on a single constellation diagram (as shown in the conceptual diagram).
I have attached the optisystem file along with the conceptual figure too.
ThanksAttachments:
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September 30, 2016 at 8:37 am #41390
Tayyab Mehmood
ParticipantHere is the basic conceptual diagram of hierarchical modulation in the electrical domain
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December 14, 2016 at 6:52 am #41830
preben
ParticipantHi,Tayyab,
do you solve your problem? I am also interested in this kind modulation in OptiSystem.
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December 14, 2016 at 7:56 am #41831
Tayyab Mehmood
ParticipantStill, did not find a solution to do hierarchical modulation in Optisystem 14.0. But succeeded to do hierarchical modulation in MATLAB.
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December 22, 2016 at 11:03 am #41875
Damian Marek
ParticipantI put this small project together to demonstrate how to do it in OptiSystem. It’s not too hard.
One of the signals is the underlying signal which is amplified by 2 and the extra signal is layered on top in each quandrant.
Regards,
Damian -
December 22, 2016 at 5:30 pm #41878
Tayyab Mehmood
ParticipantThanks Damian for replying with such a helpful material. I have done this part too in the optisystem. I am wondering how one can extract both the signals (high priority and low priority) at the receiver side . Would you please help me in this regard.
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December 23, 2016 at 8:48 am #41879
Damian Marek
ParticipantYou could make a 4 QAM Demodulator to get back the primary signal. The demodulator should be made so that it does not care about the detailed parts in each quadrant, but simply detects which quadrant the symbol is in. That would give back the first signal.
For the second it would also be a 4 QAM demodulator but with its constellation shifted into one of the quadrants. Just make a user defined IQ map.
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